1. Field of the Invention
The present invention relates to machines for the machining of parts from very long profiles that may present a certain flexibility, especially to machines meant for the formation of aeronautics parts, starting from extruded aluminum profiles or bars.
2. Description of the related art including information disclosed under 37 CFR .sctn..sctn.1.97-1.99
There are already known a few machines for the machining of parts from very long profiles. Among these machines, there is one that, schematically, comprises a base, two mandrels, means to mount the two mandrels in cooperation with the base so that they are capable of (a) displacement in translation relative to the base following an axis of a machining operation and also of (b) pivoting around that same axis, a machine to govern the mandrels, and machining mechanisms capable of cooperating with the profiles or bars to machine the part of same that is located between the two mandrels.
The machine works in the following manner. First, there is made to slide into the two mandrels, the profile or bar from which must be made parts of a specific shape, in a manner such that one of the ends of the profile or bar is placed in a first mandrel, the longest part of the profile or bar being offset relative to the second mandrel. The portion of the profile or bar that is to be machined then is held between the two mandrels, and is perfectly rigid, the small distance between the two mandrels not making it possible for it to suffer any deformation, by flection for example.
It is then possible to operate the machining mechanisms, suitable to execute the part in the pre-set shape, for example boring, routering, etc. using tools that work between the two mandrels.
When the machining of that part of the profile or bar is completed, the first mandrel is loosened and, without loosening the second mandrel, its displacement is actuated in translation toward the first mandrel, this driving along the profile or bar in the same displacement. When the two mandrels are as close to each other as possible, there is actuated the re-tightening of the first mandrel and the loosening of the second one that is displaced in translation in the direction opposite that of the previous displacement, to get it back at some distance of the first mandrel.
The second mandrel is re-tightened and the machining means again can be actuated according to the pre-set program in order to work on the new portion of the profile that is defined and held between the two mandrels.
The above-described operations are repeated as many times as necessary to execute, in the profile or bar, the part of pre-set shape, until the second end of the profile or bar reaches the level of the second mandrel, if needed.
There is thus seen that the above-described machine does not permit to optimize the machining of profiles because it is obvious that the successive displacements of the mandrels, as well as their loosening and re-tightening to release then block the profile or bar, lead to unavoidable positioning errors that add up at the time of each translation of the second mandrel relative to the base. The precision of these machines therefore is average because of these cumulated, and not, necessarily, repetitive errors in the machining of long parts.
The above-described successive operations, further, do not make it possible to act on the profiles or bars and on the machined parts while the same still are on the machine tool, for example for other operations of control, of marking or of forming (rim-holing).